Conventionally, as a connector for performing connection of a three-way stopcock and infusion tubes such as transfusion tubes, there has been known a tapered type connector having a lock mechanism (for example, refer to Patent Literature 1). A male-side connector constituting the connector is equipped with a lock ring having a female screw, about a male luer. Further, a female-side connector is equipped with a female luer fitted to the male luer, and a male screw screwing with the female screw of the lock ring.
The female-side connector and the male-side connector are coupled by screwing together the male screw and the female screw, while fitting the male luer and the female lure together, and the coupling is being locked thereby. Further, in a vicinity of an end portion of a screw ridge of the male screw, a latch portion by a resilient member is provided, so that, with respect to screwing together of the male screw and the female screw, the screwing together of the male screw and the female screw is fixed by the screw ridge of the female screw of the lock ring running onto the latch portion.